In a study just published in the journal Health Education Research -with Dr. Femke van Nassau as first author- we investigated if and to what extent the Dutch Obesity Intervention in Teenagers (DOiT) program was implemented as intended and how this affected program effectiveness. We collected data at 20 prevocational education schools in the Netherlands. We assessed seven indicators that may reflect implementation succes: recruitment, reach, dosage, fidelity, satisfaction, effectiveness and continuation. Data collection involved questionnaire research among teachers and pupils, adiposity measures among the pupils. From the data we derived an implementation index scores. The percentage of accomplished activities in the participating schools ranged from 9 to 93%. The percentage of lessons delivered decreased from 74 to 18% towards the end of the program. Fidelity to the teacher manual ranged from 85 to 26%. In general, teachers were satisfied with the DOiT lessons and teaching materials. Despite teachers' satisfaction with the DOiT lessons and teaching materials, degree of program implementation was lower than expected, especially towards the end of the program. Further, some evidence was found for an association between a higher implementation index score and program effectiveness.
